This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. The overall goal of the present study is to develop a system for long[unreadable]lasting inhibition of gene expression in the brain or ovary that can be used to cause permanent infertility in dogs and cats. This application is a collaborative effort between the University of Iowa (UI) and the Oregon National Primate Research Center (ONPRC). During the past six months we have performed several experiments aimed at achieving the objectives of the original application. These experiments involve the use of a bio-panning strategy to identify peptide epitopes that can be delivered via the blood stream and specifically home to cells in either the hypothalamus or the ovary of the rat to deliver RNAi. To date, we have performed three rounds of bio-panning and recovered phage clones from both the hypothalamus and the ovary that can now be subjected to additional rounds of bio-panning to finally select candidates that specifically home to the hypothalamus, ovary or both, and that can therefore be used for the next phase of the study: re-directing viral tropism of AAV based on these selected epitopes to deliver RNA interference to those particular cell populations.